*3.2.2. Genotoxicity*

Both soluble and particulate forms of chromium induced chromosome damage in sperm whale and North Atlantic right whale skin cells. We measured genotoxicity by induced chromosome damage in two ways: Percent of metaphases with damage and total damaged chromosomes in 100 metaphases. In sperm whale cells 1, 2.5, 5, 10 and 25 uM sodium chromate damaged 7, 17, 20 and 31 percent of metaphases, respectively, and induced 7, 16, 24 and 40 total aberrations, respectively. At the highest dose cell cycle arrest occurred and no metaphases were seen. In right whale cells 1, 2.5, 5 and 10 uM sodium chromate damaged 7, 15, 23 and 33 percent of metaphases, respectively, and induced 8, 18, 30 and 48 total aberrations, respectively (Figure 3A and 3B). For lead chromate, 0.5, 1, 3 and 5 ug/cm2 lead chromate damaged 6, 12, 15 and 27 percent of metaphases and induced 7, 13, 24 and 28 total aberrations, respectively in sperm whale cells. 0.5, 1, 2, 4 and 5 ug/cm2 lead chromate damaged 16, 19, 23, 32 and 26 percent of metaphases and induced 17, 22, 28, 40 and 30 total aberrations, respectively (Figure 3C and 3D).

Skin Biopsy Applications in Free Ranging Marine Mammals: A Case Study of Whale Skin Biopsies

**Figure 2. Cytotoxicity of Chromium in North Atlantic Right Whale and Sperm Whale Skin Cells.**  This figure shows the relative survival of cells treated for 24 h with chromium. There is a concentrationdependent decrease in the number of surviving cells. Error bars represent the standard error of the mean from three independent experiments. A) Cells treated with sodium chromate; B) Cells treated

with lead chromate.

as a Valuable and Essential Tool for Studying Marine Mammal Toxicology and Conservation 115

**Figure 1. Chromium Levels in Whale Skin.** This figure shows levels of Cr found in whale skin biopsies. A) This panel shows individual levels of Cr detected in each of seven North Atlantic right whales; B) This panel shows the mean levels of Cr in sperm whales grouped by region +/- the standard error. Number in parentheses on the x-axis indicate the number of whales sampled in that region; C) This panel shows the average level of Cr found in North Atlantic right whale and sperm whale skin. The North Atlantic right whale average is based on 7 animals biopsied in the Bay of Fundy. The sperm whale average is based on 331 animals biopsied worldwide.

**Figure 1. Chromium Levels in Whale Skin.** This figure shows levels of Cr found in whale skin biopsies. A) This panel shows individual levels of Cr detected in each of seven North Atlantic right whales; B) This panel shows the mean levels of Cr in sperm whales grouped by region +/- the standard error. Number in parentheses on the x-axis indicate the number of whales sampled in that region; C) This panel shows the average level of Cr found in North Atlantic right whale and sperm whale skin. The North Atlantic right whale average is based on 7 animals biopsied in the Bay of Fundy. The sperm

whale average is based on 331 animals biopsied worldwide.

**Figure 2. Cytotoxicity of Chromium in North Atlantic Right Whale and Sperm Whale Skin Cells.**  This figure shows the relative survival of cells treated for 24 h with chromium. There is a concentrationdependent decrease in the number of surviving cells. Error bars represent the standard error of the mean from three independent experiments. A) Cells treated with sodium chromate; B) Cells treated with lead chromate.

Skin Biopsy Applications in Free Ranging Marine Mammals: A Case Study of Whale Skin Biopsies

**Figure 3. Genotoxicity of Chromium in North Atlantic Right Whale and Sperm Whale Skin Cells.** 

concentration-dependent increase in the amount of damage. Error bars represent the standard error of the mean from three independent experiments. A) Percent of metaphases with damage in cells treated with sodium chromate; B) Total aberrations in 100 metaphases in cells treated with sodium chromate; C) Percent of metaphases with damage in cells treated with lead chromate; D) Total aberrations in 100

This figure shows the genotoxicity of a 24 h chromium treatment in whale cells. There is a

metaphases in cells treated with lead chromate.

as a Valuable and Essential Tool for Studying Marine Mammal Toxicology and Conservation 117

Skin Biopsy Applications in Free Ranging Marine Mammals: A Case Study of Whale Skin Biopsies as a Valuable and Essential Tool for Studying Marine Mammal Toxicology and Conservation 117

116 New Approaches to the Study of Marine Mammals

**Figure 3. Genotoxicity of Chromium in North Atlantic Right Whale and Sperm Whale Skin Cells.**  This figure shows the genotoxicity of a 24 h chromium treatment in whale cells. There is a concentration-dependent increase in the amount of damage. Error bars represent the standard error of the mean from three independent experiments. A) Percent of metaphases with damage in cells treated with sodium chromate; B) Total aberrations in 100 metaphases in cells treated with sodium chromate; C) Percent of metaphases with damage in cells treated with lead chromate; D) Total aberrations in 100 metaphases in cells treated with lead chromate.
